Wrist pin



Der. 18, 1923.

W. AAB

WRIST PIN Patented lflec. i8, i923.

kfinirn sr.enre.s

WILLIAM AAB, OF NEW ULw, MINNESOTA.

VJRIST PN.

Application filed March 27, H222. Serial No. 547,014.

To all 107mm it may concern.'

Be it known that l, i'TrLLrAii Ane, a citizen of the United States,residing` at. New Ulm, in the county of Brown andState ot Minnesota,have invented certain new and nse'tnl rnproveinents in Vrist Pins; and ido hereby declare the following to be a full. clear, and exactdescription of tie invention, such will enable others skilled in the artto which it appertains to malte and use the saine.

rlhis invention relates to a wrist pin to be used with a connecting` rodand the invention is particularly designed to'r use with the wrist pinso't internal combustion engines. Such wrist pins are asn-ally carried inbosses or lugs inthe piston and are ernbraced at the central portion bythe connecting rod. lt is quite important that the wrist pin tightly andaccurately lit its seat in the piston. It is also neeessary anddesirable, after the engine has been run quite a while at tiinesv totighten the wrist pin in the piston the saine Otten becomes slightlyloose troni wear. Y

It is an object olI this invention. therefore, to provide a wrist pinhaving a concentric opening therein7 which pin is split longitudinallyand has an expanding niember driven into and held in said split portion.

lt is also an object of this invention to provide an expanding memberwhich e2;- tends across the concentric opening in the wrist pin and isheld in operative position by the wall ot said opening.

These and other objects Aand advantages of the invention will be inllyset forth in the following description made in conneo tion with theaccompanying drawings in which like reference characters refer to thesaine parts throughout the different views, and in which Fig. l is aview partly in elevation and partly in section of a wrist pin showing`the same in relation to the piston and connectA ing` rod, a portion otlthe latter portion being shown in dotted lines;

Fig. 2 is a vertical section on the line 2--2 ot Fig. l;

Fig. 3 is a view in end elevation as seen from the right in Fig. l;

Figs is a partial top plan view of the wrist pin; I Fig. 5 is a view inelevation oit a inodiiied 'foi-n1 ot wrist pin. a portion thereof beingshown in section;

Fig. G is a view in vertical section taken on the line 6 6 of Fig. 5.showing a portion ot the connecting rod in dotted lines;

Fig. Tis view in elevation ot a further modiiied forni ot wris pin. aportion of which is shown in section;

Fig. 8 is a view in vertical section taken on the line 8-8 ot Fig. 7;

Fig. 9 is a view in elevation of a 'further inodilication, a portionbeing shown in section; and

Fig. i() is a view in vertical section on the lin-o l-l0 ot Fig. 9.

Referring to the drawings. in Fig. l is shown the outline of a pistont'or an internal combustion engine ot' the automobile type having thelugs o t'or receiving the wrist pin l and showing the connecting rod Z)embracing the said wrist pin. ln accordance with this invention, thewrist pin l is provided with a concentric opening 2 and the pin islongitudinally split or provided with a slit A tapered opening extendslongitudinally ot the pin substantially centrally ot the split 3 andthis opening` is designed to have driven therein a tapered expandingniernber or key 4. lt desired, the pini may be iforincd with a boss orreinforced portion surrounding the tapered opening receilring the pin 4,as shown in Figs. 2 and 3. The ltey il. after being driven and fitted inplace, is cut ofi' so that its large end is substantiaily tlush with theend ot the wrist pin and it is secured in place by bending' its sinallond to one side, the pin being cnt away at l to accommodate thebent-over end ot the ineniber Ll.

The wrist pin can thus be quickly and accnrateb`- ntted into the pistonlugs and the expanding :fnei'nber etiiciently held in its cor rectposition. ln case the wrist pin becomes loose in the lugs i 'troni weer,the pin can be 'further expanded and again tightly fitted in said lugsby drivingr the key el to further i, the pin l and the said l ey canagain beheld in its adjusted position by again bending over the endthereot'.

ln the inodiiicaton shown in Figs. 5 and the iin is shown harinai a slitor split extending longitudinally thereoi" into the concentric opening 8extending through the pin. A, tapered opening is torined substant-allycentrally of the slit 7 adapted to relOO llt)

ceive the tapered expanding member or key 9. The large end of this keywill, likewise, be cut oli' fiush with the end of the pin 6 and the keyWill be held in place by bending the small end slightly to oneside tolie in the cut-out portion 6 of the pin. Thfs pin Will be fitted to thepiston the same as the pin 1 and thel key 9 can be further driven in toexpand the pin G to take up any looseness occasioned by wear.

In the modification shown in Figs. 7 and 8, the pin 1() is shown havingthe concentric opening 11 and having a longitudinally extending split orslit 12. This split is also formed substantially centrally thereof withan inwardly radially tapered opening adapted to receive an expandingmember 13. This expanding member is provided with a portion 142 whichextends across the opening 11 and is seated in a longitudinally taperedgroove 15 formed in the opposite vfall of opening 11. It will be seenthat as the member 13 is driven into the pin, the same vvill be forcedinto the tapered opening in the slt and the ring will be thus expanded.The expanding member Will be held to its operative position byengagement with the slot 15 and the same will be locked in position inthe wrist pin by slightly bending over one corner thereof at` the righthand end of the pin, as seen in Fig. 7, in a manner similar to thatdisclosed in Figs. 1 to 6. From the structures in Figs. 7 and S it willbe clear that this pin can readily be fitted to Ithe piston by expandingthe same by the member 13 and that the pin can be further expanded bythe expanding member to take up any looseness occasioned by Wear.

In the modification shown in Figs. 9 and 10, a pin 16 is shown ha Yingthe concentric opening 17, the split or slit 1S communicating therewithand ivhich has a longitudinally tapered opening extending substantiallycentrally of the split 18. This latter opening is designed to receivethe expanding member 19 which is longitudinally tapered in vvidth. Thisexpanding member 19 also has a portion extending across the opening 17which is seated in a longitudinally extending groove 2O in the oppositevvall of said opening. This groove 2O is of uniform depth. It willreadily be seen that the ring will be expanded as the member 19 isdriven thereinto. VVit-h this type of expanding member. the same Will becut off at its large end flush with the end of the pin and its small endwill also lie flush or Within the end of the pin, a corner of the Samebeing bent to one side to hold said member or key in position. In Fig.9, the key is shown as extending at each side of the pin and isillustrated in this position before being cut olf and fastened in thesaid pin.

From the above description it is seen that applicant has provided asimple and improved type of Wrist pin. Such a pin can be accurately andproperly fitted in the piston in a-much shorter time than the ordinarywrist. pin and does not require. the services of an expert mechanic. Theinvention shown herein is a development of the Wrist pin shown in thepatent granted to the applicant November 25th, 1919, No.'1,322,991. Hehas found by experiments that the pin can be more easily and cheaplymade with the concentric opening. The concentric opening further givesan even distribution of metal about the pin. The expanding memberfurthermore balances the metal taken out at the split portion and thebalance of the pin is not destroyed.

It has also been found that the Vangular shaped expanding member or keysare preferable to a perfectly round key as it is much easier to obtainand maintain a uniform bearing surface on the former. Vhilc in the'structures illustrated the expanding member is shown as being held inplace by bending over the end thereof, it will be understood that thesame may be fastened in any suitable manner.

The pin of this invention when placed in position has the split portionextending across the longitudinal axis of the connecting rod as shown-inFig. 6. In operation, the connecting rod bushing or bearing bore Wearsat the top and bottom and very little if any at the sides. When theWrist pin is expanded by the key, it Will, when placed as stated expandat the top and bottom and thus effectively take up the Wear in thebearings. In installing the pin especially in replacement Work, the sameis placed in position and the engine run a While. After the bearingshave gotten to run smoothly, the pin is slightly further expanded bymovement of the expanding key and the pin thus brought to a perfect fitand bearing. The top and bottom surfaces of the pin do not wearappreciably and they thus maintain their cylindrical curved surface sothat when the pin is subsequently expanded, it Will nicely lill the Wornportions of the connecting rod bearing and give a perfect fit. As thepin does not revolve but only oscillates through a small angle,perfectly round pin is not needed, for as stated there is practically noWear on the sides of the pin. Y

It ivill also be understood that various changes may be made in theform, details and proportions of the parts Without departing from thescope of applicants invention, which, generally stated, cons-ists in thematter shown and described and set forth in the appended claims.

that is claimed is:

l. A hollow Wrist pin for connecting rods having a concentric opening ofuniform cross sectional area extending longitudinally Lernetherethrough, said pin being longitudinally split and lie-Ying e.tapered opening extending substantially centrally through the seid splitportion and en expanding key disposed in said tapered o1. ening leavingthe greater part ot' seid first mentioned opening nnoh strncted.

2. A hollow Wrist pin 'for connecting rods having a. concentriccylindrical open uniform cross sectional liorinetion e v inglongitudinally theretlironghu said pin being longitudinally split andVharing n tapered opening extending longitndinellj,7 thereofsubstantially centrally of szi'd split. and an expanding niein'berdisposed in said letter Opening' and haring n portion extending across'the cone-entrie opening in the pin and hearing egei ist the .inner pr'tion there-- of to hold the seid xp-eneing nieinher in position.

A wrist in for l ing nr eoneentrio cylindrical..- ing theretlrongh, sa'dpin nelly split and l n vving ered openiig extending longitud.nnillj)7thereot substantiallv cen'trnll I of said s Jlit and an exninr f .1. ling ineniber disposed in sind etter 'openn 0- l und having a narrow 'iett ooi ion extent across seid eoncentrie opening in the seid )in havinge. slot ornied i ogening in which the smid portion ie expanding ineniheris disposed.

A connecting r d Wrist Qin gto-r antonioe engines, seid completed pinhe.'ing l ning therethrough of a dinneter inor than halt 'the externaldinnieter of the nin and said pin being split and hor f tapered recessextend s longitudinnll e` tapered lief.' distrnlly ot seit.. split, endposed in sind recess having its sin; bent laterally to hold the seine inposition.

l e nin.

in the Weil o. il. hollow Wrist pin for connecting rods heffing enopening Ktending entirelyY thorothrongh concentric `with its periphew.seid pin being split at one side and limi g n tegeed recess extendinglone' dinelly seid split and n tapered key disposed in seid recess andsecured therein.

in testimony 'whereof l allie' in); signature.

